Material lift truck



June 14, 1960 w. s. HOLM MATERIAL LIFT TRUCK I5 Sheets-Sheet 1 FiledMarch 29, 1956 INVENTOR. WALTE R BHOLM ATTORNEYS June '14, 1960 w. B.HQLM 2,940,625

MATERIAL LIFT TRUCK Filed March 29, 1956 3 Sheets-Sheet 2 ATTO R N EYSJune 14, 1960 w, HQLM 2,940,625

MATERIAL LIFT TRUCK Filed March 29. 1956 IN VEN TOR. WALTE R 8. HO LM BYe2 ATTORNEYS MATERIAL LIFT TRUCK Walter B. Helm, 233 SE. H St., GrantsPass, Oreg.

Filed h/lar. 29, 1956, Ser. No. 574,909

16 Claims. (Cl. 214-4560) The present invention relates to material lifttrucks, and particularly to trucks which are adapted for the handling oflumber and similar material.

The primary object of the invention is to provide an attachment for lifttrucks which will permit the forks of the truck to move longitudinallyof the truck While supporting a load thereon.

Another object of the invention is to provide a lift truck attachment ofthe class described above which will permit lateral movement of a stackof lumber with relation to a freight car without overbalancing the lifttruck.

A still further object of the invention is to provide an attachment forthe lifting forks of a lift truck which will permit the lifting forks tobe tilted, along with the load thereon.

A further object of the invention is to provide longitudinally movableforks on a lift truck in which the action of the forks can be controlledcompletely from the drivers seat.

A still further object of the invention is to provide a lift truckattachment of the class described above which will be inexpensive tomanufacture, simple'to use, and durable in service. 1

Other objects and advantages will become apparent in the followingspecification when considered in the light of the attached drawings, inwhich:

Figure l is a fragmentary side elevation of the invention with a dottedline showing of the forks in elevated retracted position.

Figure 2 is a diagrammatic view of the circuits involved in thehydraulic system of the invention.

Figure 3 is a fragmentary front elevation of the invention shownpartially in section for purposes of clarity.

Figure 4 is an enlarged fragmentary vertical crosssection taken alongthe line 44 of Figure 3, looking in the direction indicated.

Figure 5 is an enlarged fragmentary vertical section taken along theline 5-5 of Figure 3, looking in the direction indicated.

Figure 6 is an enlarged fragmentary vertical crosssection taken alongthe line 6-6 of Figure 3, looking in the direction indicated.

Figure 7 is a horizontal transverse cross-section taken along the line77 of Figure 3, looking in the direction indicated.

Figure 8 is a fragmentary rear perspective view of the attachmentremoved from the lift truck.

Figure 9 is a transverse cross-section taken along the line 99 of Figure1, looking in the direction indicated.

Referring now to the drawings in detail wherein like reference numeralsindicate like parts throughout the several figures, the referencenumeral 10 indicates a conventional lift truck of the type including aframe 11, and suitable power means (not shown). A conventional verticallift assembly indicated at L is pivotally supported to the frame 11 ofthe truck 10 as indicated at 12 in Figure l. A movable brace 13 supportsthe lift assembly L from a point adjacent the rear of the lift truck'10.

rates atent j 2,940,625 Patented June 14, 1960 'ice The lift assembly Lof the lift truck 10 can be tilted at an angle to the vertical by anysuitable means. not here shown connected to the brace 13. Theconstruction described above is conventional and forms no part of thepresent invention.

The lift assembly L includes a pair of vertical channels 14 mounted inspaced apart parallel relation and pivoted at their lower ends to theframe 11 at the point 12. The channels 14 are connected adjacent theirupper ends by means of a cross-channel member 15. A pair of secondarychannels 16 are mounted in facing parallel relation between the channels14 and are adapted to vertically reciprocate with relation to thechannels 14;

Trunnion wheels 18 are journalled to the lower ends 19 of the channels16, as best seen in Fi-gures'l'and 8, and are adapted to operate withinthe vertical channels 14. A hydraulic cylinder '20 is mounted upon thecross-brace 21 formed on the lower ends of the vertical channels 14 andhas the upper portion thereof fixedly secured to the cross-frame 15extending between the upper ends of the vertical frames 14. A piston rod22 is slidably mounted within the hydraulic cylinder 20 and has itsupper free end portion fixedly secured to a cross-frame member 17secured to the upper ends of the vertical frame 1% by welding or anyother suitable meansyas best illustrated in Figure 3. The piston rod 22supports the secondary frame 15 and is adapted to raise and lower theframe 16 with relation to the vertical channels 14 and the lift truck19.

A fork supporting carriage C is mounted for vertical reciprocation inthe channel frames 1-6 and consists of a pair of vertical frame members23 joined at their top edges by a cross-member 24. Laterally extendingframe members 25 and 25A are secured to the frame members 23in anysuitable manner, such as welding or the like. Trunnion wheels '25 arejournalled to the vertical frame member 23 of the carriage C and engagewithin the channel 16, as illustrated in Figure 7.

A pair of cables 27 have one of their ends fixedly secured to thecarriage C at the point 23 with their opposite ends fixedly secured tothe cross-frames 15 at 29. The cables 27 are trained about the sheaves30 mounted to the cross-member 17 at the upper end of the vertical frame16. In the operation of the carriage C, when the piston rod 22 is inlowered position the carriage C will be at its-lowermost elevation aswill be the vertical channel member 16. When hydraulic fluid is appliedto the cylinder 20 the piston 22 will rise raising the vertical frame 16and the sheaves 30 causing the cable 27 to raise the carriage to the topof the vertical frame 16 at the upper limit of their travel. The abovedescribed elevating mechanism L and carriage C is of conventionaldesign.

The present invention consists of an attachment to providelongitudinally movable forks for the carriage C. The mechanism forsupporting the forks is indicated by the letter F. Referringparticularly to Figures 3, 4, 5, 7 and 8, it can be seen that the forksupporting mechanism consists of a basic frame member 31 having asecondary transverse frame 32 mounted parallel thereto and spacedtherefrom by the pair of cylindrical vertical frame members 33, the basemember 31 is connected to the carriage C by means of the links 34 and34A. The links 34 and 34A are pivotally connected to the base members 31and and 35 and have their opposite ends connected to the shafts 36 whichare secured to the transverse frame members 25 of the carriage C by thecars 37 and side frames 37A of the carriage.

Tubular members 36A are positioned on the shafts 36 to space the arms 34and 34A relative to the carriage C. A bracket 38 is clamped to thetransverse frame member 25 of the carriage C by the clamping plate .39and extends upwardly and forwardly therefrom. The bracket 38 is furthersupported on and secured to the cross-member 24 of the carriage C bymeans of an inverted U-shaped jaw 40 'which is adapted to engagedownwardly over the crossmember 24, as illustrated in Figure 6.

transverse cross-frame 32 of the fork lifting unit F by 7 means of pivotpins 45. 44 are adapted to contact the face 48 of the transverse basicframe member 31 maintaining toes 49 of the forks 44 in a horizontalposition. V

' The lateral spacing of the forks 44 can be varied along the supportingshafts 45 in the following manner. Taperedpins 47A pass through theopenings 47B in the transverse member 32 and register with the crossslots 47D formed on the upper ends of the lift forks 44. The heel 47 ofthe fork 44 comes against the transverse member 25A of the carriage C inthe construction of the supporting unit F. The fork holding unit F issupported on the rollers 50 when the unit is in partially extended orextended position, as illustrated in Figure 1. The rollers 50 arejournalledto the forks 51. The forks 51 have plungers 52 forming partsthereof which are adapted to operate within the cylindrical frames orcylinders 33 providing guides for supporting the forks 51 relative tothe unit F. Hydraulic cylinders 53 are pivotally connected to thecross-frame 32 by means of pivots 54 while their piston rods 55areconnected at 56 to the forks 51. The hydraulic cylinders 53 areadapted to raise and lower the forks 51 together thereof. a

I Referring now particularly to Figure 2, the hydraulic with the rollers50 on the lower end pump-57 of the lift truck 10 is diagrammaticallyillus- The heels 47 of the lift forks the pump 57 by means of a pipeline 60 so that in one 1 position of the valve 59 fluid from the pump 57will be delivered to the upper ends 61 of the cylinders 53 and in theother position of the valve 59 fluid will be delivered to the lower ends63 of the cylinders 53. Thus, the control a valve 59 will regulate theposition of the rollers with relation to the supporting surface overwhich the forks 44 are being moved.

In the use. and operation of the invention, when it is desired to pickup a load of material, such as lumber, the

fork supporting mechanism F will be in the broken line position shown inFigure '1 and will be lowered to the ground surface so that the forks 44may enter under a stack of lumber by forward movement of the lift trucka bed B of the flat car. The valve 59 is then operated to 7 7 causefluid'from the pump 57 to flow to theupper ends 61 of the cylinders 53thus transferring the weight of the load 62 from-the carriage C to therollers 50.

v The carriage 'C is then further lowered-r withrelation to the truck 10so that the forks 44 through the operation of the links 41, 34 and 34Aare causedto move away from the carriage C across the bed 3 of the flatcar. When the load' 62 reaches the opposite side of-the flat car, or thefinal position desired, the valve 59 is reversed permitting the forks 44to lower the load 62 onto support timbers T, thus releasing the load 62from the forks 44 and permitting the forks-44 to be withdrawn from underthe load 62 by backing the lift truck 10 away from the flat car. Ifthere is insufiicient space for backing of the lift truck 10 away fromthe fiat car to disengage the forks 44 the carriage C can be raisedwhich will act to pull the forks 44 from under the load 62 and into theposition illustrated in dotted lines in Figure 1. In removing the load62 from the bed B of the flat car, the opposite action takes place, withthe load 62 being lifted onto the forks 44 by means of the cylinders 53and rollers 50, and then picked up by the lift truck by raising thecarriage C in the usual manner.

Having thus described the preferred embodiment of the invention, itshould be understood that numerous structural modifications andadaptations may be resorted to without departing from the scope of theappended claims.

What is claimed is:

l. A lift truck attachment for lift trucks of the type having avertically extending frame and a carriage mounted for verticalreciprocation on said frame comprising; links pivotally attached to saidcarriage extending forwardly of said truck, a second frame carried bythe forward ends of said links, a pair of hydraulic piston and cylinderunits secured at one set of ends to said second frame, a support rollerfor each unit, the supporting rollers being carried by the opposite endsofsaid units for engagement with a surface, means supplying hydraulicactuating fluid to said units to raise said second frame with respect tosaid rollers, and a pair, of spaced lift forks carried by and extendingforwardly of said second frame.

2. A device as claimed in claim 1 wherein means are provided on saidlift truck for. vertically moving said carriage and said forks securedthereto by said links independently of the hydraulic piston and cylinderunits secured to said second frame.

3. A device as claimed. in claim '1 wherein means are provided on, saidsecond frame for supporting said forks 'for lateral adjustment thereon.

4. A lift truck attachment for lift trucks of the type having avertically extending frame and a vertically reciprocating carriagemounted in said frame comprising; a pair of forks positioned forwardlyof said carriage, a second frame supporting said forks, a first linkmeans connecting the lower portion of said second frame to saidcarriage, a second link means connecting the upper portion of saidsecond frame to said carriage and extending .parallel to said first linkmeans, at least one of said link means including aplurality of links,each of said links having one end thereof pivoted'to said carriage andthe opposite end thereof pivoted to said second frame, ground engagingmeans on said second frame for raising said second frame and said forksindependently of said carriage, and means on said lift truck for raisingsaid carriage on said. frame raising said forks therewith.

5. A device as claimed in claim 4 wherein the means for raising saidforks independently of said carriage includes a pair of hydraulic rams,a roller for 'each'ram, the rollers being carried by the lower ends ofsaid rams,

and remotely controlled means for supplying hydraulic actuating fluid tosaid rams.

6. A device as claimed in claim 4 wherein said forks are laterallyadjustable on said second frame.

7. An attachment for a lift truck of the type having a vertical mast anda carriage movable along the mast, a load-engaging unit, and meanspositively connecting said load-engaging unit to said carriage operableto project said load-engaging unit forwardly of said carriage as aresult of lowering movement of said carriage at a time when saidload-engaging unit is resting on a supporting surface.

8. An attachment for a lift'truck of the type having a a verticallymovable carriage, a fork; unit for said carriage, means for moving saidfork unit longitudinally of the truck, said means including a pluralityof parallel links connecting said fork unit to said carriage formovement from a lower position adjacent said carriage to a positionforwardly of said carriage and at a higher level relative to saidcarriage, said means also including rollermeans on said fork unit sothat upon lowering movement of said carriage at a time when said rollermeans are in contact with a supporting surface, said fork unit will beurged to move forwardly to a projected position with respect to saidcarriage.

9. An attachment for lift trucks of the type having a verticallyextending mast and a power operated vertically reciprocating carriage onsaid mast, comprising a load-engaging unit, means positively connectingthe load-engaging unit to said carriage operable to project saidload-engaging unit from a position adjacent said carriage forwardly ofsaid carriage upon lowering movement of said carriage at a time whensaid load-engaging unit is resting on a supporting surface, saidconnecting means being capable of transmitting a lift ng force from saidcarriage to said unit of sufiicient magnitude to lift said unit and itsload by virtue of an upward movement of said carriage only afterretracting said unit to said position adjacent said carriage, saidconnecting means mounting said load-engaging unit on said carriage forvertical movement with respect to said carriage independently of themovement of said carriage, and means on said load-engaging unit adaptedto engage a supporting surface for raising and lowering saidload-engaging unit relative to such surface independently of themovement of said carriage to enable said load-engaging unit to pick upand deposit a load.

An attachment for a lift truck of the type having a vertical mast and acarriage movable vertically along the mast, comprising a secondarycarriage having load-engaging means, means connected said carriages tosupport the secondary carriage for swinging movement from a lowerposition adjacent the first-named carriage to a second position spacedforwardly of said first-named carriage and disposed at a higher levelrelative thereto so that said secondary carriage may be projectedforwardly of said firstnarned carriage by swinging the secondarycarriage relative to said first-named carriage in an upward and forwarddirection.

11. An attachment for a lift truck of the type having a vertical mastand a carriage movable along the mast, comprising a secondary carriagehaving load-engaging means, means connecting said carriages to supportthe secondary carriage for swinging movement from a lower positionadjacent the first-named carriage to a second position spaced forwardlyof said first-named carriage and disposed at a higher level relativethereto so that said secondary carriage may be projected forwardly ofsaid first-named carriage by swinging the secondary carriage relative tosaid first-named carriage in an upward and forward direction, and meansfor maintaining said secondary carriage in an upright position duringits movement relative to said first-named carriage.

12. An attachment for a lift truck of the type having a vertical mastand a carriage movable vertically along the mast comprising aload-engaging unit, means connecting said carriage and load-engagingunit and supporting said load-engaging unit in depending relation fromsaid carriage in a position below the carriage and providing for upwardand forward swinging movement of said loadengaging unit to a positionprojecting forwardly of the carriage and at approximately the same levelso that when the carriage is lowered, the load-engaging unit may bebrought into engagement with a supporting surface and may move outwardlyalong such surface by virtue of this upward and forward movementrelative to said carriage, and means for effecting such movement of saidload-engaging unit.

13. An attachment as set forth in claim 12 in which the last-named meansincludes roller means on said load-engaging unit for rolling engagementwith said supporting surface.

14. An attachment for a lift truck of the type having an upright mastand a carriage movable vertically along the mast comprising aload-engaging unit, means positively connecting the load-engaging unitto said carriage for projecting the load-engaging unit from a positionadjacent said carriage forwardly of said carriage upon lowering movementof said carriage at a time when said loadengaging unit is resting on asupporting surface, said connecting means mounting said unit on saidcarriage for vertical movement with respect to said carriageindependently of the movement of said carriage, roller means on saidload-engaging unit for engaging a supporting surface to support saidload-engaging unit independently of the means connecting said unit tosaid carriage, and means for vertically moving said roller meansrelative to said unit to adjust the height of said load-engaging unitrelative to said surface to enable a load on said load-engaging unit tobe deposited on a suitable support and to enable the loadengaging unitto properly engage a load.

15. An attachment as set forth in claim 14 in which the load-engagingunit includes a pair of horizontal loadengaging fork arms.

16. A load-handling means comprising a vertical guide, a carriagemovable along said guide, a load-engaging unit, means connecting saidunit to said carriage and supporting said load-engaging unit independing relation from said carriage in a position below the carriageand providing for upward and forward swinging movement of saidload-engaging unit to a position projecting forwardly of the carriageand at approximately the same level so that when the carriage is loweredthe load-engaging unit may be brought into engagement with a supportingsurface and may move outwardly along such surface by virtue of thisupward and forward movement relative to said carriage, and means foreffecting such movement of said load-engaging unit.

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